reCaptcha v2 check with PHP

reCaptcha check.php

//check if its submited and not empty
if($this->input->post('g-recaptcha-response') && !empty($this->input->post('g-recaptcha-response'))){
    	//your site secret key
        $secret = '6LeI4RcTAAAAAKDCD8gNAxyl2_82Rrn0M6S0UTAV';
        //get verify response data
        $verifyResponse = file_get_contents('https://www.google.com/recaptcha/api/siteverify?secret='.$secret.'&response='.$this->input->post('g-recaptcha-response'));

        //decode and store the response data
        $check = json_decode($verifyResponse);
		
//check if its passed
	        if ($check->success == true) {
	        	echo "successfully pass";
	        }else{
	        	echo "try again";
	    	}
	}else{
		echo "captcha not submited";
	}
}